U.S. patent number 6,051,795 [Application Number 08/880,023] was granted by the patent office on 2000-04-18 for gimballed grommet having sections with different melt temperatures.
This patent grant is currently assigned to TA Mfg. Company. Invention is credited to Bruce S. Fisher, Ronald A. Jackson, Kevin D. Loveall.
United States Patent |
6,051,795 |
Fisher , et al. |
April 18, 2000 |
**Please see images for:
( Certificate of Correction ) ** |
Gimballed grommet having sections with different melt
temperatures
Abstract
A grommet disposed in a panel hole to prevent a fire from
spreading from one panel side to the other has a pair of flaps
defining a socket for nesting in the panel hole in a closely fit
relationship. Preferably one flap is longer than the other and is
disposed against the panel surface. The grommet has an inner
peripheral surface, preferably annular, defining a hollow central
opening with a radius less than that of the cable so as to receive
and retain the cable even with changes in cable positioning. The
grommet has a fire resistant chemical composition which becomes
resiliently flattened upon the cable disposition in the grommet
opening. One flap is bent toward the other with the panel withdrawn
from the socket and is resiliently pressed against the panel with
the panel in the socket. The grommet includes, in the section with
the larger flap, a fire resistant fabric (e.g. ceramic) impregnated
and coated with the fire resistant chemical composition (e.g.
silicone with an approximately 55 Rockwell hardness). The chemical
composition of the grommet in the section with the larger flap
preferably has a higher melting temperature than the chemical
composition of the other section.
Inventors: |
Fisher; Bruce S. (Burbank,
CA), Jackson; Ronald A. (Glendora, CA), Loveall; Kevin
D. (Pasadena, CA) |
Assignee: |
TA Mfg. Company (Glendale,
CA)
|
Family
ID: |
24063209 |
Appl.
No.: |
08/880,023 |
Filed: |
June 20, 1997 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
518254 |
Aug 22, 1995 |
|
|
|
|
Current U.S.
Class: |
174/153G;
16/2.1 |
Current CPC
Class: |
H02G
3/081 (20130101); H02G 15/013 (20130101); Y10T
16/05 (20150115) |
Current International
Class: |
B64D
45/00 (20060101); H02G 15/00 (20060101); H02G
3/08 (20060101); H02G 15/013 (20060101); H01B
017/26 () |
Field of
Search: |
;174/153G,153R,152G,152R,65G,151,157,65SS ;16/2.1
;106/18.12,18.11 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kincaid; Kristine
Assistant Examiner: Cuneo; Kamand
Attorney, Agent or Firm: Roston; Ellsworth R. Fulwider
Patton Lee & Utecht, LLP
Parent Case Text
This is a Continuation of application Ser. No. 08/518,254, filed
Aug. 22, 1995, now abandoned.
Claims
We claim:
1. A grommet for disposition in a hole in a panel and for reception
of a cable having a radius, including,
a member formed from a tire resistant material,
the member being shaped to provide a pair of flaps defining a
socket for receiving the panel in a particular relationship,
the member having at its inner end an inner peripheral surface
defining a hollow opening for receiving the cable, the inner
peripheral surface having an annular surface with a radius less
than the radius of the cable and with resilient properties to
provide for a flattening of the member upon the disposition of the
cable in the hollow opening in the member,
the member having an outer peripheral surface continuous with the
inner peripheral surface,
the member having a chemical composition providing a fire resistant
material, and
a fabric disposed in the member near the outer and inner peripheral
surfaces of the member and having heat resistant properties, the
fabric being impregnated and covered with the fire resistant
material,
the fabric being disposed near the inner and outer peripheral
surfaces along a portion of the member and wherein
one of the flaps is constructed to engage a first surface of the
panel and wherein
the member is made from a resilient material and wherein
the one of the flaps extends inwardly toward the other one of the
flaps, in a free disposition of the flaps, for engaging the panel
and wherein the flaps have an open end and wherein
the chemical composition of the member constitutes a silicone with
a Rockwell hardness of substantially 55 and wherein
the member has first and second portions on opposite sides of the
panel, the first portion of the member for being on one side of the
panel and including the one of the flaps and the second portion of
the member for being on the other side of the panel and including
the other one of the flaps and wherein
the first portion of the member has a higher melting temperature
than the second portion of the member.
2. A grommet as set forth in claim 1 wherein
the fabric is made from a ceramic having a higher melting
temperature than the melting temperatures of the first and second
portions of the member.
3. A grommet as set forth in claim 1 wherein
the fabric is impregnated and covered by the member and wherein the
fabric is a ceramic having a higher melting temperature than the
melting temperatures of the first and second portions of the member
and wherein
the contour of the fabric conforms substantially to the contour of
the outer peripheral surface and the inner peripheral surface of
the first portion of the member.
4. A grommet for disposition in a hole in a panel having first and
second sides and for reception of a cable having a radius
including,
a member having inner and outer ends and having a central opening
at its inner end to receive the cable in a pressed fit and having
at its outer end a pair of spaced flaps defining a socket for
receiving the panel and having a curved configuration at its
central opening with a radius less than the radius of the cable to
provide for a flattening of the member at the central opening
against the exterior surface of the cable and having a chemical
composition retarding the spread of any fire, one of the flaps
being on one side of the socket and the other one of the flaps
being on the other side of the socket, and
a fabric disposed in the member on the one side of the socket near
the surface of the member and having a composition resisting any
fire and impregnated and covered by the member on the one side of
the socket, the fabric extending from the one of the flaps to the
central opening in the member,
wherein the fabric is disposed near the surface of the member on
the one side of the socket and is made from a ceramic and
wherein
the fabric and the member have melting temperatures and wherein the
melting temperature of the fabric is greater than the melting
temperature of the member,
and wherein the chemical composition impregnating and covering the
fabric is a silicone and wherein the member has first and second
portions respectively for disposition on the first and second sides
of the panel and wherein
the fabric is disposed on one of said first and second portions and
wherein
the first portion of the member has a higher melting temperature
than the second portion of the member.
5. A grommet as set forth in claim 4 wherein
one of the flaps has a greater length than the other one of the
flaps and is bent toward the other one of the flaps and is
resilient for engaging and sealing the panel in the socket.
6. A grommet as set forth in claim 5 wherein
the fabric is disposed near the surface of the first portion of the
member in contoured relationship with the surface of the first
portion of the member and in the portion of the member with the
central opening and wherein
the first portion of the member impregnates and covers the fabric
to define the contour of the first portion of the member.
7. A grommet as set forth in claim 6 wherein
the first portion impregnating and covering the fabric is a
silicone.
8. A grommet as set forth in claim 5 wherein the first and second
portions of the member are silicones and wherein
the chemical composition of the portion of the member with the one
of the flaps has a higher melting temperature than the chemical
composition of the portion of the member with the other one of the
flaps.
9. A grommet for disposition in a hole in a panel having first and
second sides and for reception of a cable, including,
a member having inner and outer ends and having an outer periphery
at positions on the member, having at its inner end a central
opening for receiving the cable in a pressed fit and having at its
outer end a pair of flaps defining a socket for receiving the panel
and having an outer periphery communicating with the central
opening of the member, the member having a chemical composition
resisting fire,
the member including a fabric made from a material resisting fire,
the fabric being impregnated by the member and covered by the
member, the fabric having a higher melting temperature than the
member,
the fabric extending from the outer periphery of the member to the
central opening of the member and being disposed near the outer
periphery and the central opening of the member,
the member having a first portion for being on the first side of
the panel and having a second portion for being on the second side
of the panel,
the chemical composition of the first portion of the member having
a greater melting temperature than the melting temperature of the
chemical composition of the second portion of the member.
10. A grommet as set forth in claim 9 wherein
the melting temperature of the fabric is greater than the melting
temperatures of the first and second portions of the member and
wherein
the fabric has a contour corresponding substantially to the outer
periphery of the first portion of the member and the central
opening in the member.
11. A grommet as set forth in claim 9 wherein
the fabric is a ceramic and the first and second portions of the
member are silicones and the ceramic has a higher melting
temperature than the melting temperatures of the first and second
portions of the member.
12. A grommet as set forth in claim 9 wherein
one of the flaps is bent toward the other one of the flaps and the
one of the flaps is for resiliently receiving the panel in the
socket and sealing the one of the flaps against the socket.
13. A grommet as set forth in claim 9 wherein
the melting temperature of the fabric is greater than the melting
temperatures of the first and second portions of the member and
wherein
the fabric is a ceramic and the member is a silicone and
wherein
one of the flaps is bent toward the other one of the flaps and the
one of the flaps is for resiliently receiving the panel in the
socket and sealing the one of the flaps against the panel and
wherein
the fabric has a contour corresponding substantially to the contour
of the outer periphery of the first portion of the member and the
central opening in the member and wherein
the flaps have different lengths and wherein
the flap with the longer length is disposed on the same side of the
panel as the first portion of the member.
14. A grommet for disposition in a hole in a panel having first and
second sides and for reception of a cable, including,
fire resistant means formed from a fire resistant material,
the fire resistant means providing a pair of flaps defining a
socket for receiving the panel in a particular relationship,
the fire resistant means having an inner end and having at its
inner end a peripheral surface defining a hollow opening for
receiving the cable,
the fire resistant means having an outer peripheral surface
continuous with one of the flaps and with the peripheral surface
defining the hollow opening in the fire resistant means,
the outer peripheral surface of the fire resistant means having a
chemical composition providing a fire resistant surface, and
a fabric disposed within the fire resistant means along the
peripheral surface at the inner end of the fire resistant means and
along the outer peripheral surface of the fire resistant means, the
fabric being impregnated and covered by the fire resistant means
and having fire resistant properties,
wherein
the chemical composition of the fire resistant means is a silicone
and wherein the chemical composition of the silicone in a first
portion of the member is different from the chemical composition of
the silicone in a second portion of the member and provides a
higher melting temperature for the first portion of the member than
for the second portion of the member.
15. A grommet as set forth in claim 14 wherein
the fabric is disposed near the periphery of the first portion of
the fire resistant means and wherein
the fabric has a contour corresponding substantially to the contour
of the outer peripheral surface of the first portion of the fire
resistant means and to the contour of the peripheral surface of the
first portion of the fire resistant means at the inner end of the
first portion of the fire resistant means.
16. A grommet as set forth in claim 15 wherein
one of the flaps is longer than the other and wherein the fabric is
disposed near the periphery of the portion of the fire resistant
means on the same side of the member as the longer flap and wherein
the fire resistant means is a silicone and the fabric is a ceramic
and the fabric has a higher melting temperature than the fire
resistant means.
17. A grommet as set forth in claim 14 wherein
the inner periphery of the fire resistant means has an annular
surface with a radius and with resilient properties providing for
flattening the fire resistant means upon the disposition of the
cable in the hollow opening.
18. A grommet for disposition in a hole in a panel having first and
second sides and for reception of a cable having a radius,
including,
a member formed from a fire resistant material,
the member being shaped to provide a pair of flaps defining a
socket for receiving the panel in a particular relationship,
the member having an inner end and having at the inner end a
peripheral surface defining a hollow opening for receiving the
cable, the peripheral surface being annular and having a radius
less than the radius of the cable and the member having resilient
properties to provide for a flattening of the member upon the
disposition of the cable in the hollow opening in the member,
the member having a chemical composition to provide a fire
resistant surface, and
a fabric disposed in the member near the periphery of the member
and impregnated and covered with the fire resistant material,
the member having first and second portions each communicating with
an individual one of the flaps, one of the first and second
portions having a higher melting temperature than the other one of
the first and second portions.
19. A grommet as set forth in claim 18, including,
the chemical composition of the member constituting a silicone.
20. A grommet as set forth in claim 18 wherein
the chemical composition on the outer peripheral surface of the
member has a Rockwell hardness of substantially fifty-five
(55).
21. A grommet as set forth in claim 18 wherein
the flaps are for engaging individual ones of the first and second
sides of the panel and wherein
one of the flaps extends inwardly toward the other one of the flaps
in a free disposition of the flaps and wherein the one of the flaps
is capable of pivoting in a direction away from the other one of
the flaps for engaging the panel in a sealed relationship at an
open end of the socket.
22. A grommet as set forth in claim 18 wherein
the fabric is made from a ceramic.
23. A grommet as set forth in claim 21 wherein
the chemical composition of the member constitutes a silicone with
a Rockwell hardness of substantially 55.
24. A grommet as set forth in claim 21 wherein
the chemical composition of the member constitutes a silicone and
wherein
the fabric is disposed in the first portion of the member near the
peripheral surface of the first portion of the member and is
impregnated and covered with the chemical composition of the member
and wherein the fabric is a ceramic having fire resistant
properties.
25. A grommet as set forth in claim 24 wherein
the fabric and the member have melting temperatures and the melting
temperature of the fabric is greater than the melting temperature
of the member.
26. A grommet for disposition in a hole in a panel and for
reception of a cable having a radius, including,
a member having an inner end and having a central opening at its
inner end to receive the cable in a pressed fit and having a pair
of flaps at its outer end to define a socket for receiving the
panel and having a curved configuration at its central opening to
provide for a flattening of the member at the central opening
against the exterior surface of the cable and having a chemical
composition with properties to resist and retard the spread of any
fire,
a fabric disposed in the member and having a composition to resist
any fire and impregnated and covered by the chemical composition of
the member,
the member having first and second sections each having a melting
temperature and the melting temperature of the first section being
greater than the melting temperature of the second section.
27. A grommet as set forth in claim 26 wherein
the chemical composition of the member is a silicone.
28. A grommet as set forth in claim 27 wherein
the cable is annular and wherein the central opening in the member
is annular in an axial direction and wherein the fabric is a
ceramic.
29. A grommet as set forth in claim 27 wherein
one of the flaps has a greater length than the other one of the
flaps and is disposed in the first section of the grommet and is
bent toward the other one of the flaps and is resilient for
engaging and sealing the panel in the socket.
30. A grommet as set forth in claim 26 wherein the fabric is
disposed near the surface of the first section and is impregnated
and covered by the first section of the member.
31. A grommet as set forth in claim 30 wherein
the chemical composition of the member is a silicone.
32. A grommet as set forth in claim 26 wherein
the fabric is disposed near the surface of the first section of the
member in contoured relationship with the first section of the
member and wherein
the chemical composition in the first section of the member
impregnates and covers the heat resistant fabric to define the
contour of the grommet.
33. A grommet as set forth in claim 32 wherein
the chemical composition impregnating and covering the heat
resistant fabric is a silicone.
Description
This invention relates to grommets and more particularly relates to
grommets for preventing a fire on one side of a panel from
spreading to the other side of the panel.
Panels are provided in airplanes for separating one compartment
from another. Holes are provided in the panels for providing for
the passage of cables through the holes from the one compartment to
the other. The cables may illustratively pass electrical signals
from strategic terminals in the one compartment to strategic
terminals in the other compartment.
Grommets have been nested in the holes in the panels in the prior
art to secure the cables at the positions of the panels and prevent
the cables from rubbing against the panels. As will be appreciated,
the cables might otherwise chafe against the holes defining the
holes in the panels. Such chafing could expose the wires in the
cables and result in short circuits and produce fires.
The grommets now in use have had certain difficulties. They have
not been completely effective in sealing one compartment from
another to prevent a fire from spreading. They have also not been
effective in gimballing the cable so that the cable is able to
change position while still being fixedly retained within central
openings in the grommets. These problems have existed for decades
without any full resolution even though a substantial amount of
effort has been devoted, and significant amounts of money have been
expended, to resolve such problems.
This invention provides grommets which significantly overcome the
above difficulties. The grommet of this invention provides a
significant advance over grommets of the prior art in preventing
the spread of fire from one compartment to an adjacent compartment.
The grommets of this invention also provide an effective gimballing
relative to the cables extending through the grommets so that the
cables can alter their directional dispositions while being fixedly
retained by the grommets.
In one embodiment of the invention, a grommet disposed in a hole in
a panel to prevent a fire from spreading from one panel side to the
other has a pair of flaps defining a socket for nesting in the
panel hole in a closely fit relationship. Preferably one flap is
longer than the other and is disposed against the panel surface
more critical from a fire standpoint than the other surface.
The grommet has an inner peripheral surface, preferably annular,
defining a hollow central opening with a radius less than that of
the cable so as to receive and retain the cable even with changes
in cable positioning. The grommet has a resilient fire resistant
chemical composition which becomes resiliently flattened upon the
cable disposition in the grommet opening.
One flap is bent toward the other with the panel withdrawn from the
socket and is resiliently pressed against the panel with the panel
in the socket. The grommet includes, in the section with the larger
flap, a fire resistant fabric (e.g. ceramic) impregnated and coated
with the fire resistant chemical composition (e.g. silicone with a
Rockwell hardness of approximately 55). The chemical composition of
the grommet in the one section preferably has a higher melting
temperature than the chemical composition of the other section.
In the drawings:
FIG. 1 is a fragmentary perspective view of a panel separating two
(2) compartments and of a grommet nesting in a hole in the panel,
the grommet constituting one embodiment of the invention;
FIG. 2 is a sectional view taken substantially on the line 2--2 of
FIG. 1 and illustrates in additional detail the construction of the
grommet and the disposition of the grommet relative to a panel
receiving the grommet and also illustrates a cable extending
through a hole in the grommet and the ability of the grommet to
adjust with changes in the direction of the disposition of the
cable in the hole in the grommet;
FIG. 3 is a sectional view similar to that shown in FIG. 2 and
illustrates the cross-sectional shape of the grommet before the
panel receives the grommet; and
FIG. 4 is an enlarged fragmentary sectional view of the portion of
the grommet within the broken circle indicated at 4 in FIG. 3.
In one embodiment of the invention, a grommet generally indicated
at 10 is shown in FIGS. 1-4. The grommet is adapted to be disposed
in a hole 12 in a panel 14 to prevent fire on one side such as the
side 16 of the panel from spreading to the other side such as the
side 18 of the panel. The panel 14 may be disposed in an airplane
to separate the airplane into different compartments or
bulkheads.
The grommet 10 may include a section 20 preferably having an
annular configuration and integral with a section 22 also
preferably having an annular configuration. Each of the sections 20
and 22 may be formed from a silicone material having properties of
withstanding heat at elevated temperatures. Preferably the silicone
of the section 20 has a higher melting temperature than the
silicone of the section 22. The formulation of silicones with these
properties is well known in the art. A material such as a silicone
has resilient properties. The separate sections 20 and 22 are
indicated schematically in FIG. 3 and are defined by broken lines
25.
The section 20 preferably has a larger configuration than the
section 22. A fabric 24 is disposed in the section 20 at a position
near the periphery of the section 20. The fabric 24 is preferably
configured to follow the peripheral contour of the section 20 of
the grommet. The fabric 24 may be made from a suitable heat
insulating material such as a ceramic. Preferably the melting
temperature of the fabric 24 is greater than the melting
temperatures of the silicones in the sections 20 and 22. The fabric
24 is disposed such that the silicone in the section 20 impregnates
and covers the fabric.
The grommet 10 may include a pair of flaps 26 and 28 disposed
relative to each other to define a socket 30. The flap 26 is
provided on the section 20 and the flap 28 is provided on the
section 22. The flap 26 on the section 20 may extend a greater
distance from the base of the socket 30 than the flap 28 on the
section 22. Preferably the flap 26 has a bevelled surface 32 facing
the flap 28 so that the width of the socket 30 progressively
decreases with increasing distances from the base of the socket
30.
The grommet 10 is disposed so that the portion of the panel
defining the periphery of the hole 12 in the panel 14 is disposed
in the socket 30. In order for the socket 30 to receive the portion
of the panel 14 defining the hole 12, the flap 26 is bent away from
the flap 28. In this way, the flap 26 engages the panel 14 at every
position around the periphery of the hole 12.
The grommet 10 is provided with a hole 36 at its inner periphery to
receive and fixedly hold a member such as a cable 40 (FIG. 2). In
this way, the cable 40 is able to extend through the hole 12 in the
panel 14 without contacting the panel. Furthermore, the cable 40 is
protected by the grommet 10 from any fire in or near the panel. The
hole 36 is defined by an inner peripheral surface in the grommet 10
and is preferably provided with an annular configuration having a
radius smaller than the radius of the cable 40. Preferably the
portion of the hole 36 adjacent the section 20 has a smaller
diameter than the portion of the hole adjacent the section 22. The
grommet 10 may be considered to have an outer peripheral surface in
the portions of the grommet displaced from the inner peripheral
surface.
Because of the resilient properties of the silicone material in the
sections 20 and 22, the inner peripheral surface defining of the
hole 36 in the grommet is able to become flattened against the
cable 40 when the cable is extended through the hole. This enhances
the fixed disposition of the cable 40 within the grommet 10.
Furthermore, the cable 40 is able to shift from a concentric
relationship with the hole 36 (as indicated in solid lines in FIG.
2) to a non-concentric relationship with the hole 36 (as indicated
in broken lines in FIG. 2) without affecting the fixed disposition
of the cable 40 in the hole 36.
The grommet shown in FIGS. 1-6 and described above has certain
important advantages. It holds the cable 40 firmly within the hole
36 even when the cable is shifted from a concentric relationship to
a non-concentric relationship as shown in FIG. 2. Furthermore, the
grommet 10 retains the panel 14 in a close fit and a sealed
relationship in the socket 30 because of the resilient
characteristics of the flap 26. In this way, the grommet 10
prevents the cable 40 from becoming frayed, particularly when the
cable shifts position as shown in FIG. 2.
The grommet 10 also has optimal fire resistant properties in
preventing a fire on the side 16 of the panel from spreading to the
side 18 of the panel. This results in part from the larger length
of the flap 26 than the length of the flap 28. The larger length of
the flap 26 is provided because there is a greater tendency for a
fire on the side 16 of the panel 14 than on the side 18 of the
panel. It also results in part from the properties of the fabric 24
in withstanding heat. It also results in part from the increased
ability of the silicone in the section 20, relative to the ability
of the silicone in the section 22, to withstand heat. It also
results in part from the resilient characteristics of the flap 26
and the sealed disposition of the flap relative to the surface 16
of the panel. These resilient characteristics cause the disposition
of the flap 26 to conform to the disposition of the panel 14.
The chemical composition of the section 20 in the embodiment shown
in FIGS. 1-6 may be as follows:
______________________________________ Units By weiqht Components
in Composition of Section 20 ______________________________________
Dow Corning Silastic HS-50 75 Dow Corning Silastic LS-50 25 Dow
Corning Silastic FR-1 20 Varox DBPH-50 (catalyst) 0.72
______________________________________
The weight of each of the different components in the gasket 20 may
be varied by as much as approximately plus or minus five percent
(.+-.5%) without departing from the scope of the invention.
The Silastic HS-50 material is a methyl vinyl polysiloxane compound
having high tensile and tear strength and a hardness providing for
a durometer "A" of about fifty five (55) for the gasket 20. The
Silastic LS-50 material is a methyl phenyl polysiloxane. It is
desirable because it remains flexible at low temperatures such as
are encountered by an airplane on or near the ground or in the
upper atmosphere. Such compounds still exhibit good flexibility and
resilience at temperatures as low as -65.degree. F. such as occur
in unheated portions of an aircraft during flying. The Silastic
FR-1 material is added for fire resistance. It is a dispersion of
various ingredients, including platinum, in a polysiloxane. The
catalyst is Varox DBPH-50, which is sold by the Los Angeles sales
office of R. T. Vanderbilt. The catalyst provides for the curing of
the mixture of the components included in the gasket 20.
The gasket 20 may be press cured at a pressure of approximately
2000 psi and at a temperature of approximately 340.degree. F. for a
period of about 12 minutes. Then it is oven post-cured at a
temperature of approximately 450.degree. F. for a period of
approximately eight (8) hours without any pressure being applied to
the material.
The section 22 may be formulated from the materials specified for
the material 20. However, the percentages of such materials may be
varied depending upon the heat resistant characteristics desired
for the material 22 relative to the heat resistant characteristics
of the section 20. It is believed that a person of ordinary skill
in the art will know, or can easily determine, the variations to be
made in the relative percentages of the different materials to
obtain the desired heat resistant characteristics of the section
22. Of course, when the section 22 is to have the same heat
resistant characteristics as the section 22, the section 22 will
have the same composition as the section 20.
Although this invention has been disclosed and illustrated with
reference to particular embodiments, the principles involved are
susceptible for use in numerous other embodiments which will be
apparent to persons of ordinary skill in the art. The invention is,
therefore, to be limited only as indicated by the scope of the
appended claims.
* * * * *